12 Elbow Skin Changes That Correspond to Psoriasis and Nutritional Deficiencies

10. Nail Changes - Pitting, Ridging, and Discoloration

Nail changes affecting the fingers and toes often accompany elbow psoriasis and provide important diagnostic clues while reflecting underlying nutritional deficiencies that affect nail matrix function and keratin production. These changes typically include pitting (small depressions in the nail surface), horizontal and vertical ridging, discoloration ranging from yellow to brown, and onycholysis (separation of the nail from the nail bed). Nail pitting occurs in approximately 50% of psoriatic patients and results from inflammatory involvement of the nail matrix, creating characteristic small depressions that appear randomly across the nail surface. Zinc deficiency significantly contributes to nail abnormalities by impairing keratin synthesis and nail matrix function, leading to white spots, horizontal ridges (Beau's lines), and increased nail fragility. Iron deficiency affects nail health by reducing oxygen delivery to nail tissues and impairing cellular metabolism, resulting in spoon-shaped nails (koilonychia), pale nail beds, and increased brittleness. Biotin deficiency specifically affects nail keratin production, leading to soft, easily breakable nails with vertical ridging and splitting. Protein malnutrition impacts nail growth and strength by limiting amino acid availability for keratin synthesis, resulting in thin, weak nails with horizontal ridges marking periods of nutritional inadequacy. Silicon deficiency affects nail hardness and strength by impairing the cross-linking processes that provide structural integrity to nail keratin. The combination of psoriatic inflammation and nutritional deficiencies creates a synergistic effect where nail changes become more pronounced and persistent, often serving as indicators of both disease activity and nutritional status.